Unrestricted 150.

[ShuttleBug]

Does any one know which wire to cut on the cdi to eliminate the rev limiter?   Is there a manual out there in scooter land for a Super 8 150?   Who on here is the 150 guru?

[Urbestfriend]

Frankly I don't recall anyone seeking to do a derestriction on any production bike above 50 cc's.  I did cut the green wire on an Agility 50.  You can search for several posts on that.  That modification took it from 35 to 45 mph.  However there are some racing CDI's available.

[climbamt]

I would be concerned with eliminating the Rev Limiter. It is there to keep you from destroying the motor by over rev-ing.....

[ShuttleBug]

Thousands of 50s are unrestricted ! 

[johnson]

50's are restricted for speed reasons, not to protect the engine.  Plenty of revs left above the 30 mph "limit".   125's and 150's are restricted to protect the engine.

[ShuttleBug]

Thousands of motorcycles are unrestricted I have 3 in my garage, never blown any of them up either!

[Urbestfriend]

Might be in your interest to consult a scooter racing forum.  Interesting information regarding Mopeds and Motor Scooters under Wilkipedia.

[ophelia]

In general, we derestrict 49 cc bikes to remove the low rpm restriction so the bike can achieve max power. Problems arise when we defeat the max rev limiter to protect the engine from valve float and valvetrain destruction.

How powerful are your derestricted motorcycles? I believe CVTs have less gearing range or spread than a manual transmission too; thus, you would reach top gear ratio and max rpm on a small scooter very quickly doing a high speed run.

Are you hitting the rev limiter already? Usually it is only a problem going max speed downhill with a tailwind.

You may want a good tachometer and some research into the valve limits of the Kymco 150 cc. See what upgrades you need to sustain high speed valve operation. People do trash engines through overrev, downhill at top speed.

[ShuttleBug]

After searching on ebay I found a company selling a CDI that advances the timing 4 degrees and eliminates the rev limiter. They also sell an exhaust system for gy6 150 based engines for 90 bucks shipped.    scooter-atvparts

[ShuttleBug]

Update, the people selling the CDI for gy6 engines emailed me and said kymco does something different and it wont work on this engine.....

[Urbestfriend]

After reading this thread for the last few days,  the term unrestricted / derestricted might be better served as modified.
Usually this involves modified clutches,  rollers of various weights,  performance mufflers,  air intake changes and carburetor jet changes and this doesn't include larger cylinder add-ons.   Basically 125's, 150's and 250's fall in this category.
These changes are usually expensive and can be time consuming because there can be a lot of trial and error.  I had a 125 Vino that went thru two broken Yamaha Mufflers.  I replaced them with an MRP Muffler which included several jet changes.  It didn't enhance performance and lowered gas mileage.  That bike is still running fine with over 17,000 miles.  This forum can be a wealth of information.  Unfortunately sometimes there's no firm answer...then it's up to each individual as to what level risk they want to take.  Hope this has been a help. 

[ShuttleBug]

Friend, I have done a bit of reading about this subject as well, most of the mods are done on the 50cc scoots not so much on anything bigger other that a pipe jet kit or shim etc.  The clutch seems to be the best place to go for higher speeds. Maybe I will dig into that a little more.  I already shimmed my needle and the pipe is looking like the next thing.

Just as with my bikes cant leave anything stock for long.......   Gotta be others that have modded 150s. Links???